Telepresence and video conferencing have been an increasingly important component of the overall collaboration marker, which indicator is the best measure of the continued importance of these technologies going forward?（）

• A、the annual growth rate of the video-conferencing market is 23 percent
• B、generationY ,raised on video, comprises 17 percent of the world population
• C、thecisco long-term growth-rate target is 12 percent to 17 percent
• D、the U.S internet traffic annual growth rate is more than 40 percent